The present invention relates to an electron beam apparatus for projecting electron beams on a substrate.
An electron beam apparatus 100 may be used to project electron beams 135 on a substrate 130, as for example shown in FIG. 1, to generate an image comprising an electron pattern on a resist coated substrate 130. A multiple electron beam apparatus 100 comprises a chamber 110, a support 120 capable of supporting a substrate 130 in the chamber 110, electron beam source, modulating and scanning components 150 mounted on boards 140 in the chamber 110, and a vacuum pump 115 to evacuate and maintain a vacuum environment in the chamber 110. The electron beam source, modulating and scanning components 150 generate, modulate and scan an array of electron beams across the substrate 130.
An apparatus 100 that generates and modulates a few tens of individual electron beams 135 may require hundreds or even thousands of separate electrical wires 170 to electrically connect the components 150 to circuitry outside the chamber 110. Conventional apparatus 100 uses individual electrical wires 170 passing through vacuum feedthroughs 160 in a chamber wall 112 to connect to the components 150. However, the large number of electrical wires 170 passing through the vacuum feedthroughs 160 often renders the vacuum feedthroughs 160 susceptible to leakage. In addition, the complexity of the vacuum feedthroughs 160 and electrical wires 170 may make it difficult to change or modify the components 150, for example, when redesigning or adapting the electron beams for different tasks, without extensive modification of the wiring assemblies and feedthroughs 160. Also, the closely packed individual wires 170 in the feedthrough 160 may result in electromagnetic interference that causes unacceptable modulation of the electron beams 135.
Thus, it is desirable to have an electron beam apparatus having low leakage connections to the external environment. It may also be desirable to have an electron beam apparatus with an electrical connection system that is readily adapted to accommodate new circuitry without extensive modification. It is also desirable to reduce the electromagnetic interference that occurs in the electrical connection system.
An electron beam apparatus that is capable of registering an electron beam pattern on a substrate comprises a vacuum chamber having a wall, a substrate support in the vacuum chamber, electron beam source components to generate an array of electron beams in the vacuum chamber, electron beam modulator components to modulate the electron beams in the vacuum chamber, electron beam detector components to detect the electron beams in the vacuum chamber, one or more circuit boards passing through the wall of the vacuum chamber, each circuit board comprising (i) an internal portion to support one or more of the electron beam source, modulator or detector components, (ii) an external portion outside the vacuum chamber to support one or more external components, and (iii) a plurality of electrical traces that extend from the internal portion to the external portion to electrically connect the electron beam source, modulator or detector components to the external components, and one or more of the external components mounted on the external portions of the circuit boards.
In another aspect, the electron beam apparatus comprises a vacuum chamber having a wall with a first feature, a substrate support in the vacuum chamber, electron beam source components to generate an array of electron beams in the vacuum chamber, electron beam modulator components to modulate the electron beams in the vacuum chamber, electron beam detector components to detect the electron beams in the vacuum chamber, one or more circuit boards passing through the wall of the vacuum chamber, each circuit board comprising (i) an internal portion to support one or more of the electron beam source, modulator or detector components, (ii) an external portion outside the vacuum chamber to support one or more external components, (iii) a plurality of electrical traces that extend from the internal portion to the external portion to electrically connect the electron beam source, modulator or detector components to the external components, and (iv) a second feature that may be fitted to the first feature in the chamber wall to align the circuit board in the vacuum chamber, and one or more of the external components mounted on the external portions of the circuit boards.
In another aspect, the electron beam apparatus comprises a vacuum chamber having a wall, a substrate support in the vacuum chamber, electron beam source components to generate an array of electron beams in the vacuum chamber, electron beam modulator components to modulate the electron beams in the vacuum chamber, the electron beam modulator components comprising an array of beam blanking components, electron beam detector components to detect the electron beams in the vacuum chamber, and a circuit board passing through the wall of the vacuum chamber, the circuit board comprising (i) an internal portion to support the array of beam blanking components, (ii) an external portion outside the vacuum chamber, and (iii) a plurality of electrical traces that extend from the internal portion to the external portion.